Method of drying and impregnating felt



H. D. BROWN Aug. 11, 1936.

METHOD OF DRYING AND IMPREGNAL'ING FELT Filed Nov. 5, 1934 [A ME/v7-02.- HHEOLD D. 520w Patented Aug. 11, 1936 UNITED STATES PATENT OFFICEMETHOD OF DRYIliggiND DVIPREGNATING 2 Claims.

My invention relates to a new and improved method of impregnating orsaturating an absorbent material with a saturant. This application is acontinuation in part of my application en- 5 titled Method of drying andsaturating felt,

Serial No. 682,105, filed July 25, 1933.

Although my invention is useful in many of the arts wherein felt, paperor similar material is impregnated with asphalt or other saturant, myinvention has a particular utility in the roofproducing industry, andtherefore in the ensuing description I will describe my invention asparticularly applied to that industry. It should be understood that I donot wish thereby to limit my invention to the particular illustration ofthis application.

It is an object of my invention to provide a method of saturating anabsorbent with a saturant to obtain a superior product at less cost.

20 A further object of my invention is to provide a method in which theabsorbent, such as a sheet of felt or the equivalent, is submerged in abody of saturant, such as hot asphalt or the equivalent, for asuflicient length of time to coat the surfaces J of the absorbent, andthen to immediately remove the absorbent in order that the vapors formedwithin the absorbent may escape on the outside of the body of saturant.

By actual use of my invention I have found that it is superior to theprior art methods of drying and saturating a sheet of absorbent such asfelt because the apparatus employed for performing the process may beoperated at a high rate of speed, (1)) because more saturated felt maybe produced in a given time, (0) because there is a saving in labor, and((1) because there is a saving in fuel or power required to operate theapparatus and to maintain the saturant at the desired temperature. Inactual practice I 40 have found that the saving which is perfected inconnection with items (a) to (d) just recited is approximately 20% ineach instance. This value, however, may vary denpending upon actualoperating conditions.

A further object of my invention is to provide a process which willsimultaneously remove the moisture from the absorbent and saturate theabsorbent.

It is an object of mypresent invention to provide a method in whichasphalt is applied to the surfaces of the strip of absorbent material bysub merging same in a body of hot asphalt, and removing the strip offelt with such rapidity that the moisture will not materially form intovapors while the strip of felt is still submerged. In this manner thevapors are formed on the outside of the body of asphalt where they willbe liberated wihout forming foam in the asphalt. This has the decidedadvantage of enabling better penetration of the asphalt by preventingformation of foam 5 on the surface of the body of asphalt as well as onthe surfaces of the strip of felt.

It is a further object of my invention to provide a method of thischaracter in which any foam which may be formed on the surface of theasphalt will be quickly and automatically removed.

It is another object of my invention to provide a method in which astrip of absorbent material may be impregnated in a shorter period oftime than is possible by any of the common methods.

By the utilization of my invention it is possible to operate apparatusfor impregnating the-felt at such speeds that with given'materials andwith a given degree of saturation, larger quantities may be produced ina given length of time than is possible by common methods.

It is an object of my present invention to provide a method of producingasphalt impregnated felt in which the strip of felt or other absorbentmaterial is coated with asphalt or other saturant and in which shortlythereafter the saturant by a suitable pressural operation is forced intothe absorbent material.

In the preferred form of my invention I use a pressure means whichoperates against the sur- 4 faces of the strip of felt and which forcesthe saturant into the strip of felt. In the continuous process of myinvention I find that this step in my process may be satisfactorilyperformed by the use of a pair of rollers, one of which rests on theupper surface of the strip of felt and produces a squeezing action whichsqueezes or forces the asphalt into the felt strip.

The important steps of my invention may be used in the variouscombinations of other steps which are ordinarily performed in thesaturating of an absorbent material. I will describe and illustrate oneform of my invention, and it should be understood that variousalterations and modifications may be made without departing from thespirit and scope of my invention, and various steps which do notconstitute the essence of my invention may be eliminated withoutdeparting from the spirit and scope of my invention.

I will now refer to the accompanying drawing and describe the preferredform of my invention.

In the drawing:

Fig. 1 is a somewhat diagrammatic view illustrating the apparatus of myinvention.

Fig. 2 is a vertical section through the pressure rollers of theinvention adapted to impart a surface pressure to the strip of roofingmaterial in the process of treating the same, this section being takenas indicated by line 2-2 of Fig. 1. 7

Referring particularly to the drawing, I provide a relatively long andshallow tank construction II which is inclined downwardly to the left.In the embodiment shown this tank construction II is providedwith apartition I2, which divides the tank construction into tanks orreceptacles I3 and I4. To the left of this pair of tanks I3 and I4 Iprovide a large saturating tank I5.

The numeral I6 indicates a hot saturant supply pipe which, in the formof my invention disclosed, is adapted to supply hot asphalt to theapparatus. This pipe I6 has a downwardly extending branch I! whichextends into the tank I5 on the left of a partition I8 and has a branchpipe I9 which extends into the tank I5 on the right of the partition I8.This partition I8, it will be noted, divides the tank into twocompartments and 22. The hot asphalt is continuously supplied to thesetwo compartments 20 and 22 by means of the branch pipes I9 and I1 and iscontinuously removed therefrom by suitable return pipes 25.

The main supplypipe I6 is provided with a pair of branch pipes and 3|,each of which has a valve 32 and which is adapted to supply hot asphaltto the tanks I3 and I4. By means of the branch pipes 30 and 3|, a bodyof hot asphalt may be maintained in each of the tanks I3 and I4, thesebodies of hot asphalt being indicated by numerals 33 and 34. Bycontinuously supplying hot asphalt to each of these tanks I3 and I4, thehot asphalt in one tank is caused to overflow the dividing wall orpartition I2, which defines the leftward boundary of the compartment I3and will spill into the body of hot asphalt in the compartment I4. Itwill be noted that the upper end of the partition I2 is lower than therightward wall of the tank II, and that the leftward wall 35 of the tankII is lower than the upper end of the partition I2 in order that acontinuous flow will occur over the upper edges of the partition I2 andthe wall 35 in a leftward direction, as indicated at A and B in Fig. l,the overflow indicated at B spilling into the compartment 20 of the tankI5. The partition I8 of the tank I5 also provides a spillway between thecompartments 20 and 22, the asphalt overflowing continuously from thecompartment 20 into the compartment 22 as indicated at C in Fig. 1.

From the description thus far, the manner and method of supplying hotasphalt to the various tanks and compartments will be understood.

, The bodies of hot asphalt in the tanks I3, I4 and 20 are continuouslyreplenished and continuously overflow the walls or partitions I2, 35 andI8 which define the left margin of these tanks.

It should be understood, however, that I do not wish to be limited tothe specific construction shown in the drawing which is illustrativeonly, the number and arrangement of the compartments in the tanks II andI5 being, of course, dependent upon the desired number of submergingsteps in the practice of my novel method, and coming well within thescope of my basic idea.

In each of the tanks I3 and I4 is a guide means in the form of anadjustable roll, these adjustable rolls being identified by the numeralsand M. It will be noted that each roll is located below the surface ofthe body of hot asphalt contained in each of the tanks I3 and I4. Thestrip of felt or other absorbent material which is to be treated firstpasses over initial rolls 46 and then passes to the roll 40. In passingaround the roll 40, the sheet of felt is submerged in the body 33 of hotasphalt. The strip of felt then passes upwardly and between a pair ofpressure rollers P, the purpose of which will be described later. Thestrip of felt then passes around the roll M and then passes around anelevated roll 48.

From the roll 48 I show the strip of felt 45 passing around a guide roll50 which is adjustably supported in the compartment 20 of the tank I5 bya supporting mechanism 5I, including a vertically movable carriage 52 towhich is connected suitable cables 53 passing over pulleys 54 which inturn are connected to a suitable operating mechanism which includes ahand wheel 55 adapted when turned to raise or lower the guide roll 50relative to the tank I5 for the purpose of submerging the strip 45 to agreater or lesser depth in the body of hot asphalt 56 in the compartment20.

From the adjustable guide roll 50 the felt strip is passed upwardlybetween a pair of pressure rollers P which are similar to the rollers Pand which are suitably supported on the top of the tank I5. From thepressure rollers P the felt strip is again passed downwardly around aguide roll 51, adjustably supported by mechanism 58, similar to thesupporting mechanism 5I.

The felt strip 45 is then carried upwardly and passed between a pair ofsteam heated gauging rollers H, which are provided with suitablemechanism for varying the distance between the rollers for the purposeof gauging the thickness of the felt strip and of removing the excessasphalt from the surface thereof, in a manner well known in the art.

From the gauging mechanism H the strip 45 is passed upwardly around anelevated roll 59. This roll 59 and the elevated roll 48 are preferablysteam heated by suitable well known means to prevent asphalt fromcollecting and hardening on the surfaces thereof.

In the preferred form of my invention I provide adjustable guide rolls60 and BI in the compartment 22 which are comparable to the guide rolls5!) and 51 in the compartment 20.

The guide rolls 60 and 6| are respectively supported by adjustablemechanisms 62 and 63 comparable to the mechanisms 5I'and 58.

Mounted on the top of the tank I5 between the mechanisms supporting theguide rolls 60 and GI is a pair .of pressure rollers P, identical withthe pressure rolls P and P. The strip 45 is carried from the roll 60between the pressure rollers P" and is then passed around the guiderolls 6| and is then passed out of the tank I5 and between a pair ofsuitable steam heated gauge rollers G, similar to the gauge rollers H.The strip 45 is then passed to a suitable cooling looper or over anysuitable guides, such as a series of rollers similar to the roller 65provided for guiding the strip out of the apparatus.

Referring first to the pressure mechanisms P, P, and P", foraccomplishing the step in the process of applying surface compression tothe felt strip 45, it should be understood that these mechanisms may beused at various places on the apparatus. I have found it sufficient toutilize only one of. such pressure mechanisms, such as the mechanism P'at a point between the guide rollers 50 and 51 of the compartment 20, soas to provide the surface compression step of the process directly afterthe strip 45 has passed around the roller 50. It may be found to bedesirable, however, to associate one or more of these pressuremechanisms with the tank H so as to accomplish a surface compression tothe felt strip 45 between the successive steps of submerging the stripin the tanks 13 and M. For the purpose of illustration I have shown thepressure mechanism P positioned above the tank ll so that the initialsurface compression step in the process is accomplished directly afterthe initial submerging step in the tank l3.

It may also be found desirable to associate one or more of the pressuremechanisms with the compartment 22 of the tank I 5. If such a use isdesired, one of the pressure mechanisms such as the mechanism P" may bepositioned between the. guide rolls to and 6| of the compartment 22, asshown.

The details of construction and the mode of operation of the pressuremechanisms P, P, and P" will be understood more easily with reference toFig. 2 of the drawing. In this figure I show a pair of. brackets 15 and16, suitably mounted, such as in the manner shown, on opposite sides ofthe tank l5, or on a framework above the tank II, as the case may be.Each of the brackets 15 and 16 provides a bearing 11 adapted to journala shaft 18 carrying a bed roller 19, which in the preferred form ofapparatus is provided with heating means. This means might convenientlyinclude piping (not shown) for circulating steam through suitable coredpassages in the shaft 18 and through the interior of the bed roller 19.Each of the brackets 15 and 16 has formed therein, above the bearings 11a vertically extending way 88 in which a bearing block BI is verticallyslidable. The bearing blocks 8| are adapted to support a shaft 82carrying a weighted pressure roller 83.

It will be readily understood that when the felt strip 45 is passedaround and between the rollers 19 and 83 in the manner shown in Fig. 1the weighted pressure roller 83, which is freely slidable verticallyrelative to the bed roller 19, will compress the surface of the strip 45against the bed roller 19.

It is, of course, understood that the above described means for applyingsurface pressure is illustrative only, the exact details of constructionbeing immaterial, it-being well within the scope of the invention to useequivalent means of applying the desired pressure to the strip 45. Ifdesired, a spring or screw actuated roller may be used in place of theroller 83. In the preferred form of my invention, however, I prefer touse the weighted roller 83. I have found that a roller of this characterhas a'unique action, and that when used in connection with the step ofsubnierging a strip of felt in a hot asphalt greatly facilitates thedehydration and impregnation of the felt, accomplishing entirely newresults never accomplished before in the manufacture of roofingmaterial.

In this connection I will refer to the dehydrating and saturating actionwhich is carried on in the tanks l3 and I4. It will be seen that thestrip of felt 45 is submerged in the bodies of asphalt 33 and 34 but avery shallow distance, and when the strip of felt is moving at a normalrate of speed, it will be submerged for a very short length of time. Inpractice, the strip of felt is moved at such a rate of speed that thetwo surfaces thereof will be thoroughly coated, but at thesame time eachsuccessive portion, as it is treated, is removed from the body of. hotasphalt before the vapors therein are formed to any great extent, inorder that practically all of the liberation of the vapors will occurafter the treated portion of the strip of felt has been withdrawn fromthe body of hot asphalt. This action may be particularly described withrespect to the tank I3. The strip of felt passes downwardly into thebody of. hot asphalt 33, as indicated by the arrow K. The strip of feltpasses around and below the guide means or roll and then passes directlyupward in the direction of the pressure mechanism P, and each successiveportion will be therefore submerged and will be quickly emerged from thebody of hot asphalt 33 so that the liberation of the vapors will notoccur to any material extent until the treated portion is above thesurface level of the body of hot asphalt 33, where such liberation willnot cause a foaming of the asphalt contained in the tank.

Shortly after issuing from the body of asphalt 33 the felt strip ispassed between the rollers 83 and 19 of the pressure mechanism 1?, thesqueezing action imparted thereby not only serving to press or wring thestrip in such a manner as to remove the excess asphalt carried on theasphalt throughout the strip. This squeezing action also removes anyfoam or bubbles carried by the strip 45 and prevents this foam frombeing entrained into the body of asphalt in the succeeding submergingtank.

I have found that the action of these pressure rollers very materiallyquickens the thorough impregnation of the felt strip. In carrying on theprocess of impregnating roofing material without the use of the pressurerollers, I have found that while submerging the strip in asphaltthoroughly coats the outer surfaces thereof, there are frequently manypatches in the strip in which the asphalt does not readily penetrateinto the pores of the felt so that an even distribution and a uniformdepth of penetration is accomplished only after repeated submergingsteps.

By the use of the pressure rollers of my invention, I am enabled toobtain substantially complete distribution and a uniform depth ofpenetration with only a single submerging step. This I believe is due tothe fact that as the strip 45 is passed between the rollers 83 and I9the excess asphalt on the surface of the strip which is prevented by thesqueezing action of the rollers from passing therebetween, builds up, asindicated at D forming an eddy or back-wash which serves to constantlydistribute the asphalt evenly over the entire surface of the strip asthe strip is subjected to the surface compression by the rollers. Thiscompression forces the asphalt into the pores of the strip to asubstantially uniform depth and causes the strip to emerge from betweenthe rollers, free from excess asphalt on the exterior surfaces thereof,which allows perfect freedom for the escape of moisture vapor.

The hot asphalt in the tank I I is at a temperature of 400 to 450 F. andtherefore the moisture in the felt strip is very quickly vaporized. Thedehydrating action which results from this vaporization of the moistureand the liberation of such moisture vapors outside the body of saturant,being assisted by the above described action of the pressure rollers, isvery quickly and efficiently performed. This type of treatment isperformed in each of the compartments l3 and [4, although I have foundthat only the one surface compression step is ordinarily necessary for asubstantially complete dehydration of the felt strip. When the strip offelt has passed around the roll 48, it has usually been thoroughlydehydrated and is ready for subsequent treatments in the compartments 20and 22.

It is, of course, obvious that upon submerging the strip of felt in thebody of hot asphalt there is an immediate tendency toward vaporizationof the moisture content of the felt, and a small amount of vapors may begiven off immediately even though the strip of felt is very quicklyremoved from the body of hot asphalt. There is a possibility, therefore,that a slight amount of foam may collect on the surface of each body ofhot asphalt 33 and 34. This formation of foam, however, is so negligiblethat the foam does not collect to the extent that the steps of themethod will be impaired. By reason of the fact that the hot asphalt iscontinually overfiowing the partition l2 and the end wall 35 of thetanks I3 and 14, there is a continuous surface flow of the asphalt inthe direction of the left end of the tank structure H. Therefore, anyfoam which is formed on the surface of either of the bodies of hotasphalt 33 or 34 is immediately moved in a leftward direction toward thepartition [2 or the end wall 35. In passing over this partition and endwall the spilling action tends to break up any foam that might havecollected on the surface of the asphalt so that substantially no foam iscarried from one tank into the other. It is to be noted that thiscontinuous flow of hot asphalt tends to continually and immediatelyremove all foam from a position on the surface of the hot asphalt wherethe strip of felt will be contacted. This is particularly true withrespect to the place where the strip of felt enters the hotasphalt. Itis particularly desirable because there will be no foam adhering to theraw felt as it passes into the body of hot asphalt, and therefore therewill be no collection of bubbles or foam on the surface of the feltwhich might impair penetration of the hot asphalt into the pores of thefelt.

The operation of the pressure mechanisms P and P" adjacentthecompartments 20 and 22 of the tank I5 is the same as that of thepressure mechanism P described above, the eddy of excess asphalt beingbuilt up at the points E and F, and the pressure rollers 83 and 19serving to force the asphalt into the pores of the felt in an evenlydistributed manner and to a substantially uniform depth.

As before stated, the pressure mechanisms P, P, and P" need not all beused at the same time or at the identical intervals in the process whichI have disclosed. I have found that in some instances the mechanism Pmay be dispensed with, and that satisfactory dehydration is accomplishedby the guide rollers 40 and 4|, the action thereof in rapidly submergingand withdrawing the felt strip being all that is necessary to accomplishsubstantially complete dehydration. This is substantially true in'treating a light weight felt or one that has a comparatively lowmoisture content. In this event the pressure mechanism P' may be used tofacilitate the quick impregnation of the strip by forcing the asphaltinto the pores of the felt in an evenly distributed manner and to auniform depth.

I have also found by experiment that it is sometimes unnecessary tocarry on the submerging steps and the surface pressure step in thecompartment 22; in this case, the strip 45 is passed without additionalsubmersions to the guide rolls 65 or to suitable cooling loopersdirectly from the roll 59, as indicated by the dotted lines 45a inFig. 1. If the tank 22 is not used, the gauging rollers H serve as thefinal gauging mechanism in the process, acting to remove the excessasphalt from the strip so that the strip will be in suitable conditionfor drying when delivered to the cooling loopers above referred to.However, in the preferred form of my invention I consider it desirableto provide the compartment 22 and to carry on the submerging steps andthe surface compression step therein in order that any desired degree ofsaturation of the strip may be accomplished.

When, as preferred, the compartment 22 is utilized, the gauging rollersG are used as the final gauging mechanism serving to compress the strip45 to the desired thickness and removing the surplus asphalt therefrom.

It is believed that from the foregoing the method of my invention, aswell as the apparatus which I have. produced, may be readily understood.The various steps of the process and the operation of the apparatus ofmy invention may be epitomized as follows:

The strip of rag-felt or paper which is commcnly used is of a soft andporous nature and has not been previously treated to remove themoisture. Therefore, the moisture content thereof may be as high as sixor seven per cent. While mentioning the strip of felt which I haveindicated by the numeral 45, I wish it to be strictly understood that myinvention is not limited to the treatment of any particular absorbentmaterial. The strip of felt 45 passes, as indicated by the arrow K, fromthe initial rolls 46 into the tank l3 and around and below the roll 40,being submerged in the hot asphalt 33. The strip then passes upwardlythrough the pressure mechanism. It should be understood, however, that Ido not consider the pressure mechanism P essential at this point, havingmerely included it in the initial saturating steps to illustrate thefeasibility of its use at this point. I have obtained far superiordehydrating efficiencies than those obtained in other processes bymerely quickly submerging the strip and quickly withdrawing it beforethe liberation of the moisture vapors occurs and allowing these vaporsto escape before again submerging the strip. The primary feature of thepressure mechanism is the function of forcing the asphalt into the bodyof the felt strip so that even distribution and uniform depth ofpenetration can be accomplished throughout the entire strip. The stripthen passes downwardly around the roll 4| in the tank l4 and is thuscaused to be submerged in the body of hot asphalt 34. After emergingfrom the tank l4 the strip is passed around the elevated roll 48 atwhich time it is ordinarily thoroughly dehydrated. The strip is thensuccessively passed through the following steps, submerging in the tank20, applying surface pressure thereto by the mechanism P, againsubmerging in the tank 20, passing through the gauging mechanism toremove the excess asphalt therefrom, repeating the submerging steps andthe surface pressure step in the tank 22, and

finally passing through the gauging rollers G to finally remove thesurplus asphalt therefrom.

As a specific example of the factors involved in my process, thefollowing facts obtained from actual use of my invention are recited.

Referring to Fig. 1, I have used my invention in actual practice wherethe roll 40 or M is 9 inches in diameter and is submerged to a depth of1 to 1 inches below the surface of the body of saturant in which it issubmerged, and under these conditions the amount of felt in connectionwith this particular submerging step is approximately 26 lineal inches.The amount of felt which is on the exterior of the 'bodies of hotsaturant between any two succeeding submerging steps, such as betweenthe roll 40 and the roll 4|, is approximately 18 feet.

In the example now referred to the felt is traveling at 195 feet perminute. This is figured on 325 rolls of felt per hour, the rolls being36 feet to the roll of 85 pound slate surfaced roofing. The felt used is50--D felt. On this basis the rate of travel of the felt is 2,340 inchesper minute. With 26 lineal inches of the felt being submerged, any givenportion of thestrip or roll of felt will remain submerged forapproximately two-thirds of a second. In other words, it requiresapproximately two-thirds of a second for the felt to travel from thepoint where it enters the hot saturant to the point where it emergesfrom the hot saturant.

The time limits involved in my process must be varied in accordance withthe character and weight of the felt being treated, the moisture contentof the felt, and the quality, character, or consistency of the saturantused. At times it will be desirable to submerge the felt for a period oftwo seconds, and at other times it will be desirable to submerge thefelt for a period of less than twothirds of a second. Likewise, thespeed of the apparatus may be increased or decreased and the depth ofsubmergence may be increased or decreased as found desirable by thoseskilled in the art in the practice of my invention.

The essence of the invention and the basis for the process are that thefelt is submerged in the hot asphalt for the purpose of coating orapplying the hot asphalt to both sides thereof and is quickly removed sothat the vapors produced by the vaporization of the moisture or gasesproduced as a result of the heat will be released or liberated from thefelt outside the body of saturant to avoid, as far as possible, theformation of foam. As pointed out heretofore, the formation of foam hastwo injurious actions. First, it destroys the quality of the hot asphaltby providing a large body of foam and impurities on the surface thereof.and, second, the foam adheres to the surface of the felt and preventsproper saturating of the felt.

In the foregoing I have given factors which are involved in performingthe process of my invention under certain operating conditions, and

ranged as disclosed in the drawing and in accordance with the dimensionsgiven heretofore. The sizes of the parts and the speed of operation mayalso be in accordance with the foregoing specific example. If, duringthe performance of the process foaming occurs which produces the badeffects pointed out heretofore, the time of submergence of the felt maybe shortened. This will be quite obvious to one skilled in the artbecause, as specifically pointed out heretofore, the length and time ofsubmergence control the amount of foam which occurs. By shortening thetime of submergence the amount of foaming will be reduced. Likewise, theperiod of time which the felt is retained on the exterior of the hotasphalt may be varied in order that the time will be proper to allow theliberation of vapors from the felt. If, on the other hand, the felt isnot properly saturated and there is an absence of any material orsubstantial foaming, the operator skilled in the art will know that thetime of submergence is not sufficiently long to coat or impregnate thesurfaces of the felt to obtain the results pointed out inthis'specification. The operator will thereupon change the time ofsubmergence either by lowering the roller or by slowing up the speed ofthe apparatus.

In view of the fact as pointed out heretofore, it is impossible to givedefinite time limits. I have therefore pointed out the importantfeatures of my invention and the steps which must be performed in orderto accomplish the results of my invention. With the information given askilled'mechanic may readily adjust the various factors in order toobtain these results.

I believe my invention to be broadly new, and I have therefore writtenthe claims in accordance with the scope of my invention, and it isdesired that these claims be construed in accordance with the broaddefines of my invention as fully described therein.

I claim as my invention:

1. A process of the class described, including the steps of: providing abody of hot saturant;

completely submerging a sheet of absorbent in said body of hot saturantonly for such a length of time that the surfaces of said sheet ofabsorbent will becoated but not sufiiciently long that materialvaporization of moisture will occur in said sheet of absorbent; removingsaid sheet of absorbent from said body of hot saturant; and. retainingsaid sheet of absorbent on the exterior of said body of hot saturantuntil the vapors formed in said sheet of adsorbent have been liberated.v

2. A process of the class described, including the steps of: providing abody of hot saturant; completely submerging a sheet of absorbentin saidbody of hot saturant; removing said sheet of absorbent from said body ofhot saturant when the surfaces of said sheet of absorbent have beencoated by said hot saturant but before any material vaporization ofmoisture occurs in said sheet of absorbent; and retaining said sheet ofabsorbent on the exterior of said body of hot saturant until the vaporsformed in said sheet of absorbent have been liberated.

' HAROLD D. BROWN.

